package thread;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.Future;
import java.util.stream.LongStream;

public class testForkJoin {
    public static void main(String[] args) throws ExecutionException,
            InterruptedException {
//        test1(); // 5152
//        test2(); // 2143
        test3(); // 57
    }

    // 普通程序员
    public static void test1() {
        Long sum = Long.valueOf(0);
        long start = System.currentTimeMillis();
        for (Long i = Long.valueOf(1); i <= 10_0000_0000; i++) {
            sum += i;
        }
        long end = System.currentTimeMillis();
        System.out.println("sum=" + sum + " 时间：" + (end - start));
    }

    // 会使用ForkJoin
    public static void test2() throws ExecutionException, InterruptedException {
        long start = System.currentTimeMillis();
        
        ForkJoinPool forkJoinPool = new ForkJoinPool();
        ForkJoinTask<Long> task = new ForkJoinDemo(0L, 10_0000_0000L);
        ForkJoinTask<Long> submit = forkJoinPool.submit(task);// 提交任务
        Long sum = submit.get();
        
        long end = System.currentTimeMillis();
        System.out.println("sum=" + sum + " 时间：" + (end - start));
    }

    public static void test3() {
        long start = System.currentTimeMillis();
        // Stream并行流 () (]
        long sum = LongStream.rangeClosed(0L, 10_0000_0000L)
                .parallel().reduce(0, Long::sum);
        long end = System.currentTimeMillis();

        System.out.println("sum=" +sum + "时间：" + (end - start));
    }
}
